Carbohydrates (or carbs) are macronutrients, that is, they are elements from which the body is able to obtain energy. Depending on the source of the carbohydrate, they will also provide other important substances, called micronutrients, ie vitamins and minerals. According to the molecular structure they may contribute fiber.
Carbohydrates are formed by molecules called saccharides, the main unit being glucose or a monosaccharide; and depending on the type, they may present a structure that is formed by a single molecule (glucose directly) or, in turn, be formed by several molecules, polysaccharides (several monosaccharides) or even chains of them. When one of these last types of carbohydrate is ingested, our digestive system must reduce it to the molecular unit, glucose. It will then be transported through the bloodstream and serve as the primary source of energy for the brain, muscles and other tissues and cells.
Function of Carbohydrates
Their primary function is to provide energy, that is, they are an energy source or substrate that provides support for certain activities, depending on the intensity and duration of these activities.
But their role does not finish here, they also intervene in other processes and thanks to their properties they produce other benefits:
Energy supply and regulation of blood glucose
Glucose is the form in which the carbohydrates provide energy to the body (glycolysis). Therefore, even when we start off with a larger molecular structure, composed of glucose chains, it will first have to be broken down into the smaller unit. This action is performed by the digestive system involving enzymes from the liver. Blood glucose levels should remain constantly stable, due to its great importance for the cellular function.
Among the numerous metabolic functions in which the liver intervenes, the regulation of glucose levels is one of them. When we ingest food, a signalling system is triggered that detects the increase in blood glucose levels, and as a result, insulin will be secreted. Insulin can bond with a multitude of cells that have the appropriate receptors and for this reason the absorption of glucose will take place. In the liver, this insulin will cause the absorption of glucose, and in addition, the synthesis of glycogen.
There is another hormone, glucagon, which is secreted into the bloodstream when glucose levels are low. It inhibits the cells absorption of glucose, and stimulates the use of hepatic glycogen, producing its discharge into the bloodstream. On the other hand, glucagon also produces a physiological phenomenon called gluconeogenesis, whereby the synthesis of glucose from certain amino acids takes place.
The liver has a limited capacity to supply glucose, so that after a period of not more than 24 hours, it is necessary to ingest or seek other sources of glucose. In fasting periods, the fatty acids are mobilized from the adipose tissue and transported through the blood flow to the skeletal muscle which will begin to use them as substrate to obtain energy. However, our brain can not make use of this resource, as the fatty acids can not cross the blood-brain barrier. The next stage will be that the muscle tissue will supply amino acids that will be transported to the liver to produce new glucose (gluconeogenesis). If the fasting continues for more than a day, the body can enter a state called ketosis, which is motivated by a lack of glucose, and the need for the body to "carry on working".
Although the body can find an alternative route to obtain glucose, or work directly with another type of "fuel" as in the case of ketosis (where ketones are used), it is not very advisable, especially for athletes.
Furthermore, a regular intake of carbohydrates will result in not having to resort to proteins to synthesize new glucose (reducing gluconeogenesis).
Related to ketosis, our brain can adapt to the use of ketones as a source of energy, although it prefers glucose. To prevent ketosis, and ensure the use of glucose, we must ingest a minimum of carbohydrates (approximately >50g). If we intend to adapt to the use of ketones, the first symptom that we will suffer will be headaches.
Carbohydrates are not Essential
As we have just explained, and unlike proteins and fats, which provide essential amino acids and essential fatty acids, respectively, carbohydrates are not necessary for human life. This is because the body has the adequate mechanisms to produce glucose from other sources, such as proteins and fats. However, the most advisable, and above all, efficient, option to obtain glucose, is from the contribution of carbohydrates, to produce energy and store it.
This is a minor function. There are receptors in the tongue that detect the sweet taste and send a signal to the brain. Sweeteners can be classified into two types: nutritive or non-nutritive.
In the first case, the contribution is linked to an intake of calories, which we can metabolize and use as energy. Within this type we can distinguish (extended description ahead): sucrose, glucose, fructose, high fructose corn syrup, and lactose. On the other hand, non-nutritive sweeteners do not contribute calories, but they do cause the same sensation in our brain. These may include: saccharin, cyclamate, xanthan gum, sucralose, and acesulfame.
We can find a source of fiber in carbohydrates from cellulose, hemicellulose, pectin, and mucilage. Fiber makes the excretion of waste products much easier. Due to the fact that dietary fiber is both non-digestible and a water attractant, feces become large and soft, which will facilitate their evacuation (with less pressure). If there is a considerable amount of pressure this can lead to certain problems in the gut, such as diverticula, or hemorrhoids.
Consumption of fiber can prevent weight gain, because of the relation between the space it occupies in the stomach and its low calorie contribution, the consumption of a smaller amount of this type of carbohydrate will provide us with a greater sense of fullness and satiety.
Consuming fiber is also related to reducing the Glycemic Index, GI, of food (a concept explained below) and the absorption of cholesterol.
Insulin and Carbohydrates
Insulin is a hormone that allows the body to use glucose. It is secreted by the pancreas when the presence of glucose in the bloodstream is detected, and will either produce the storage or the use of this energy. Insulin helps maintain stable blood sugar levels, avoiding hyperglycemia (high levels of glucose), after eating, and hypoglycemia (when there is a decrease of glucose levels), such as after physical activity. Because of this, insulin helps to balance blood glucose and keep it at the right levels. If the blood sugar level increases, the pancreas secretes more insulin.
There are two concepts related to insulin and the content and type of carbohydrates: the Glycemic Index and the Glycemic Load.
The Glycemic Index (GI) is a value assigned to food products based on how fast they can increase glucose levels. In the GI food table, the higher the rate, the faster the release of glucose into the bloodstream. Therefore, the greater the stimulation of the pancreas, increasing the secretion of insulin. On the other hand, foods that have a lower GI, will offer more sustained energy properties, in contrast to those with high index, which can cause "insulin peaks", ie a very abrupt response of this hormone, with a short time energy use.
We consider the following GI for food:
Low GI: <55
Medium IG: 56-69
High GI: >70
The other factor that is used to understand the physiological effect that the carbohydrate-containing foods have on us, and which may be more comprehensive, is the Glycemic Load (GL) because it addresses several features: it will take into account GI, and the grams of carbohydrates per serving of food.
This way, a food product can have a high GI, but a low GL, that is, it does not contain such a high amount of carbohydrates that it can drastically affect the increase of insulin.
To calculate the GL:
GL = (GI x grams of carbohydrate) / 100
The GL table will classify food according to:
Low GL: <10
Medium GL: 11-19
High GL: >20
Observations on GI and GL
The two concepts are relevant when it comes to eating food that exclusively contains carbohydrates, as in the presence of other macronutrients, such as proteins and fats, their response may be altered. The conclusions drawn from the two concepts is that both of them are necessary to know how we are affected by carbohydrates, and thus use them at our convenience in the sports field. With respect to GL, despite obtaining a low value, we can make it increase, if of course, we consume a higher amount of said food.
Types of Carbohydrates
The classification encompasses 2 types of carbohydrates: simple and complex. The difference between the two lies in the molecular structure and how fast they are absorbed and digested. Simple ones will be treated much faster than complex ones.
They have a simple structure, formed by a single molecule, the simplest form being glucose. They are known as simple sugars or monosaccharides. The word monosaccharide means "mono" one, and "saccharide" sugar.
Due to its molecular structure the body can process them very quickly, obtaining a brief energy response, after which there is a descent that coincides with the end of its use. The term "sugar" as such is a name given to a group of these carbohydrates which have a short chain, cyclic structure, and with the characteristic sweet taste.
Within this group we can find several types:
Types of Sugars or Monosaccharides
Glucose: The main sugar that our body metabolizes for energy.
Fructose: The sugar contained in fruit. It is the sweetest and most water soluble of all sugars.
Galactose: Normally found in nature in large quantities, it also combines with glucose to form milk lactose. It is usually found in legumes. After being absorbed by the body, galactose is converted to glucose in the liver. It is much less sweet than glucose or fructose.
Types of Disaccharides
Most of the sugar we ingest are disaccharides, because they are a mixture of two of the above monosaccharides. The properties of sweetness, absorption speed and how they affect our body depends on which sugars are combined.
In this way, we will be able to find the following types of disaccharides:
Sucrose: Also known as table sugar, is formed by the combination of glucose and fructose. Although sucrose can be found in plants, only cane sugar, which is born in tropical climates, and sugar beet, which is grown in colder regions, contain enough amounts to make the extraction viable.
Inverted Sugar: It is similar to sucrose, but while in sucrose, the glucose and fructose molecules are bound together, in the case of inverted sugar they are free. That's why its taste is sweeter than that of sucrose.
Lactose: The sugar in milk. It is a type of disaccharide formed by the combination of glucose and galactose. The molecular binding they form is called the beta-glucosidic bond, which for certain people can be difficult to digest, and therefore many people are intolerant to lactose, causing them stomach discomforts.
Maltose: Maltose is found mainly in germinating grain, particularly barley, and is less sweet than glucose, fructose and sucrose. It consists of two molecules of glucose.
They are polysaccharides, that is, they consist of a large number of glucose units. For this reason, they allow the storage of large amounts of glycogen. Starch is the main form of carbohydrate storage in plants, and we can find it in grains, seeds, and root vegetables. Starches are a key part of the diet. About 50% of our carbohydrate intake comes from there. The main sources of starch are potatoes, beans, bread, pasta, rice and other bread products.
Starch can be divided into two types: amylose and amylopectin, each of which has different properties. The amylopectin constitutes about 80% of the starch. The amylose has a colloidal structure in suspension while the amylopectin is insoluble in water. While amylose is a straight chain polymer, amylopectin is highly branched.
Glycogen is stored in the liver and muscle. Although glycogen is structurally similar to amylopectin, as they are both polysaccharides, it has more branches and these are shorter. Amylopectin can form stable starch gels that are capable of retaining water, while amylose is unable to do so.
Having explained both types of carbohydrates, depending on the sport activity, and especially the time, we can benefit one or the other.
Benefits of Carbohydrates for Sport
All the energy we need for life is provided by the food and liquids we eat. Such nutrients are acquired from carbohydrates, fats and proteins. Each of these categories has relation to a certain health function, and in general terms, we should try to consume of all these food sources. Although the ratio and proportion of each one should be defined in terms of the person.
This time we are going to focus on the role of carbohydrates in sport and the benefits they offer.
This macronutrient is the most efficient energy source for athletes and sportspeople, no matter what type of discipline is performed, as they will provide energy for muscle contractions. When ingested, if they are of the complex type, they must be digested and metabolized to the glucose unit, that is, to the monosaccharide structure, which will reach the cells and be used by them. If we ingest glucose directly, it can go to the reservoirs, in the liver and muscle, or be used directly as energy.
The form in which glucose is stored is called glycogen, thus we can speak of hepatic and muscular glycogen. Glycogen will be present in any activity that exceeds a threshold of intensity, especially if it is explosive and has a limited duration. In the case of activities of longer duration the energy substrate used will be a different one, such as fat. However, there will always be an overlap of all substrates.
An adequate carbohydrate intake will help avoid using proteins as an energy source, which despite the fact that the body has the resources to do so, is not the most efficient way of obtaining energy. The protein’s function is to build and support the tissues that make up the body: muscle, bones, skin, hair..., so if we limit the consumption of carbohydrates, this will entail that we will not have enough protein for it to carry out its own activities. Likewise, if we resort to generating glucose from proteins, it will cause extra stress on our kidneys and other systems that are involved, because this process produces metabolic waste products that must be excreted.
Energy from Carbohydrates
Each gram of carbohydrate provides 4kcals of energy. Additionally, when stored, they take water with them, at a rate of just under 3g of water. This implies that once we finish our workout if we ingest carbohydrates, our weight may rise, but it will be due to the fact that the storage of glycogen is retaining water in the muscle tissue.
Glycogen is a limited energy source, ie the body has a finite deposit. Certain very intense and long-lasting activities can lead to the depletion of glycogen, and therefore it is imperative to restore them or else the activity will cease or not be performed at the rate we wish.
It is common to find the expression "the wall" and it means that the athlete has used up, or almost emptied their glycogen stores, being forced to abandon the activity.
Athletes and sportspeople resort to the "carbohydrate loading" strategy, which consists of planning days before the glycogen depletion that is going to happen in a sports event. With the objective of filling the glycogen reserves to the maximum, allowing to face the competitive event. In this situation the carbohydrate intake is increased in much higher proportions than when a conventional diet is performed. To facilitate this task, we use supplements based on carbohydrates.
Carbohydrates during exercise
As we have mentioned, the carbohydrate deposits are limited, and despite a carbohydrate load, according to the duration of the event, we might be forced to replenish this energy during the course of it.
Under this scenario, possibly opting for carbohydrate supplements is the most efficient and optimal way to continue with the intensity of activity.
Carbon Carbohydrate Supplements
We have described the fundamental aspects of Carbohydrates, and above all, their influence in the sports field. Next, we will go on to list and explain what kind of carbohydrates we can find as sports nutritional supplements, why they are beneficial and when and how to take them.
Carbohydrates for Daily Nutrition
This section shows the types that we would no include in the sports field, carbohydrates used in food recipes, given that their purpose is different. As we have seen in the description, this type of products is related to maintaining health:
Oat flour is a ready to use flour obtained from oat cereal. Its properties are that it provides a low GI, therefore, the release of glucose into the blood will be carried out slowly and progressively, and the glycogen load will increase gradually. The ideal moments to take it would be at breakfast, or in the meal prior to our workout. It offers a great versatility and range of recipes when consuming it: with protein shakes, in the form of pancakes or biscuits…
Rice flour has a similar function to the previous product, however, in this case the GI is higher, so it would be beneficial to use it before or after training. It also offers the possibility of being used as an ingredient in recipes or mixed with protein shakes.
Fiber favours digestion, the intestinal tract movement, helps to fight certain diseases, and is also needed for certain tasks.
Sucralose is a non-caloric sweetener used to sweeten any recipe.
Xanthan gum is a type of polysaccharide that is used in certain recipes because of its thickening properties.
Carbohydrates for Sports Nutrition
In this point we will specify the different supplements focussed on the peri-workout (explained below), whose contribution is a valuable resource for athletes. They will achieve certain improvements in physical performance, such as:
Effective energy supply
Allowing to maintain the intensity of the activity
Increase the duration of the activity
What is Periworkout?
Peri-workout is the period of time that spans from the moments before, during and after physical activity. It is a temporary window that we can allocate according to the time-slot in which we will perform our training. Thus, we can locate the Periworkout in the morning, noon, or afternoon.
We can distinguish two types, depending on the time margin that we are in, around the physical activity:
Out of the Periworkout time
In the Periworkout time
The meals that are outside of this time window, and according to our diet, should have Complex Carbohydrates.
Palatinose is a type of carbohydrate derived from sugar, but with the peculiarity that unlike sugar, it has a low GI. This will allow us to administrate the energy on a sustained basis. It is ideal combined with other supplements with a higher GI because it will generate an energy backup if we are going to perform a long-lasting activity. Therefore, it can be taken within the Peri-workout. Otherwise, if our goal is carbohydrate loading, it can be eaten at any other time of the day.
Amylopectin offers a number of characteristics that justify its use as a carbohydrate drink for training:
High molecular weight, which will help to generate an optimal recharge of the glycogen stores, thanks to the easy energetic availability provided by the glucose units
Low osmolarity, which will provide a rapid transit and gastric emptying
Amylopectin has a high GI, however, due to its properties, it will behave facilitating an efficient refill of the glycogen stores.
Cyclodextrins are an enzymatically modified type of amylopectin to obtain a superior product. It is the best type of carbohydrate available for sports use because it provides a faster carbohydrate recharge, and without causing any stomach upset.
Maltodextrin is a type of polysaccharide carbohydrate, that provides a high GI, but due to its molecular structure (formed by branching glucose chains) it can maintain the energy supply in a sustained way, as before it can render energy the bonds must be “broken”, ie, it has to be decomposed into the final glucose units.
Dextrose is a type of monosaccharide, that is, it will provide glucose directly. The benefits of dextrose can be obtained when looking for a rapid increase in insulin, such as after training, or in combination with another lower-response carbohydrate, during training.
The gels are ready-made carbohydrate formulas to be taken and administered during workouts providing a rapid energetic response. It should be noted that after this rise in glucose their may be a drop in blood glucose, for which you may need to ingesting another gel to stabilize the levels. It is usually recommended to be used in the intervals in a competition when energy reserves are at a minimum, or after a long period of time. They can also be taken just before a maximum effort, such as a mountain pass climb, or a speed test.
Carbohydrates for Pre-Workout
In this period we are looking for a contribution that provides us with energy throughout the training. We must establish how many carbohydrates depending on the time of day, according to the meals we have eaten, the grams of carbohydrates in these intakes... It is best to produce a mild insulin response, to avoid any type of hypoglycemia, or if you can be prone to it.
The most recommended carbohydrate supplements for this moment would be:
Carbohydrates for Intra-Workout
Due to the circumstances of this period, resorting to supplementation is possibly the most viable option: our body is immersed in the exercise, which consequently means that the blood is distributed around the periphery of the body, reason why ingesting solid food could suppose stomach discomforts.
The most recommended carbohydrate supplements for this moment would be:
Carbohydrates for Post-Workout
At this moment the preferred option is to look for a high GI carbohydrate to favour the increase of insulin and to quickly procure glycogen load. In such a case, any of these types of supplements would be perfectly combinable, and can be taken along with supplements of Protein Shakes, Amino Acids, and/or Creatine.
The most recommended carbohydrate supplements for this moment would be:
At HSNstore you can find for sale all the varieties of carbohydrates that have been explained above. We offer a wide range of the best quality and always at unbeatable prices in our HSN brand products.